Unknown unix metadata version +12

Hello everybody and Merry Christmas,

I have been using UrBackup in a business environment for about 1.5 years now and have not had any major problems so far.

But since a few days I have got an error message in the backup log of a client, which I can’t get on with:

Unknown unix metadata version +12 in "/mnt/backup/urbackup_tmp_files/78"

I even reformatted the backup hard disk (/mnt/backup/), the SMART values are good and it’s only one client that is causing problems.

Do you have an idea how I can get ahead here? Here is some technical information:


  • Debian Buster 10.2 in a VM on a Proxmox-Host
  • UrBackup Server 2.4.12


  • Debian Stretch (9.11), a Proxmox-Host
  • UrBackup Client (going to update this one)

Thanks in advance!

The log line should be followed by “Copied metadata to FN for error analysis”. If possible send that file to bugreports@urbackup.org (it contains file metadata of all the files being backed up).

I’m not sure where I can find that file, there’s also no such line in the log?

Can you change the code? If yes change https://github.com/uroni/urbackup_backend/blob/c7c80cc5636496ade779f8b37dbfbfbd6eaca02f/urbackupserver/FileMetadataDownloadThread.cpp#L454

if (isComplete())



You do get the Error saving metadata. Could not save OS specific metadata to FN later?

Edit: If possible please post the whole log with log level information.

I’m using the debian packages, so I’m not sure if I can change the code without installing from source?

You do get the Error saving metadata. Could not save OS specific metadata to FN later?

No, no occurrence of that message. I attached the full log.

logfile.txt (155,3 KB)

Seems it is a debug level message. So if you put the server into debug logging mode it should go into the log file (see Having problems with UrBackup? Please read before posting )

Installing from source shouldn’t be that hard. See https://www.urbackup.org/server_source_install.html

Symlink the db location beforehand (mkdir -p /usr/local/var && ln -s /var/urbackup /usr/local/var/urbackup) and install a few dependencies (apt install build-essential zlib1g-dev plus perhaps a few configure tells you about)

I’ve sent the debug log to bugreports@urbackup.org.